1. Firstly, go to Appearance > Customizer and delete both Link Color and Accent Color at Colors

2. Paste (or update) below css in your style.css file

.genesis-nav-menu a:focus,
.genesis-nav-menu a:hover,
.genesis-nav-menu .current-menu-item > a,
.genesis-nav-menu .current-menu-parent > a,
.genesis-nav-menu .sub-menu .current-menu-item > a:focus,
.genesis-nav-menu .sub-menu .current-menu-item > a:hover {
	color: #15a9a9;
	text-decoration: none;
	background:#f2f1f6;
}